Limited access and escalating costs of health care persist despite decades of attention to these problems. Telemedicine, conceived as an integrated system of health-care delivery that employs telecommunications and computer technology as a substitute for in-person contact between provider and patient, has previously been used mostly as a tool to address geographic barriers that prevail in rural areas. Telemedicine might also enhance access and increase efficiency of routine pediatric care in urban and suburban settings. Rigorous assessment of the reliability and efficacy of pediatric telemedicine is a pre-requisite to studies of its clinical effectiveness in routine pediatric practice and of its impact on cost. Improved access and efficient use of clinician time through telemedicine is readily envisioned. Because it changes interactions, however, telemedicine s impact on quality is uncertain, and it is likely to vary with the nature of the clinical problem. Data on the quality of telemedicine and on its strengths and weaknesses in addressing various clinical issues is important to providers, payers, regulatory agencies and consumers. Telemedicine's allure may be tempered or strengthened by quality tradeoffs or augmentation. The specific aim of this study is to assess the reliability (reproducibility of diagnosis and treatment decisions) and efficacy (safety; time requirement; patterns of testing, consultation and referral; understanding of parent concerns; and visit completion) of telemedicine for common, acute complaints of children presenting to the emergency department or primary care office setting. Hypotheses will be assessed using a dual-evaluation crossover study design. For 8 clinical problem groups, 100 childhood illness episodes presenting to an emergency department or a hospital-based primary care center will be evaluated by both telemedicine and in-person clinicians. Broad applications of telemedicine in routine pediatric practice are plausible and plentiful. These efficacy and reliability studies have been designed as a first step in preparation for several applications. For example, telemedicine might be used to replace a large proportion of emergency departments and office visits, to enhance communication and reduce burdens associated with chronic childhood illness, and to strengthen home-based alternatives to inpatient care for children.